"We are ready and eager to take on this Delta launch," Col. Greg Wood, launch commander and vice commander of the Air Force's 30th Space Wing, said in a statement earlier this week. "We are proud to provide this national defense capability, and every Team V member involved has tirelessly worked to ensure the launch is safe and successful."

"The 4th Space Launch Squadron's mission assurance technicians, engineers, and program managers are laser-focused on ensuring that all flight hardware, infrastructure, and facilities are ready to go for launch," said Maj. Allen Varghese, 4th Space Launch Squadron director of operations. "Our squadron has worked side-by-side with ULA personnel over the past several months to ensure this mission's success."

On Sunday, a top secret government spacecraft launched by SpaceX reportedly failed to achieve a stable orbit. The government hasn't confirmed whether the top-secret satellite did indeed fall out of orbit and reenter Earth's atmosphere.

In the aftermath of the alleged failure, SpaceX claimed its rocket performed as expected, implying the blame for the Zuma mission lay elsewhere.

Sunday's launch was SpaceX's third classified mission. This week's launch will be ULA's 27th mission for the NRO. The mission offers ULA a chance to show why the aerospace company remains the government's most trusted partner for top-secret missions.

Tomorrow's launch will be live streamed. Coverage will begin at 3:40 p.m. ET.